Project Summary/Abstract: Cerebrovascular imaging has a broad impact in a variety of brain disorders, including cerebrovascular diseases such as stroke, arterial stenosis, Moymoya disease, small vessel diseases, and vascular dementia, but also in other neurological conditions such as brain tumor and traumatic brain injury. Current clinical practice of cerebrovascular imaging requires multiple scans and, in some cases, multiple visits in order to obtain a complete assessment of the brain?s vascular health that includes perfusion, hemodynamic parameter, and flow reserve. This limitation increases patient burden and significantly escalates the cost of care. Therefore, the goal of the present project is to develop novel methods to perform an integrated vascular (iVas) imaging that provides all relevant physiological information in a single scan (<10 minutes). The proposed iVas-MRI technique will apply concomitant O2 and CO2 gas inhalation (but with different timing) and will simultaneously measure cerebral blood volume (CBV), cerebrovascular reactivity (CVR), bolus time-to-peak (TTP), and functional connectivity networks from the same dataset. Aim 1 will develop three key components of the iVas-MRI technique, specifically concomitant O2 and CO2 gas-inhalation paradigm, high spatial-resolution MRI pulse sequence, and multi-parametric data processing algorithm. A cloud-based computation platform will also be developed for standardization of the analysis and future dissemination of the technique. Aim 2 will conduct validation and multi-vendor assessment of the iVas-MRI technique. We will compare results of the iVas-MRI technique to those of standard techniques and will examine across-vendor reproducibility of the proposed technique by scanning each participant on three MRI systems manufactured by General Electric, Philips, and Siemens, respectively. Aim 3 will apply the technique in patients with Moyamoya disease and study its potential value in both the diagnosis and treatment monitoring of this condition. We will first examine the utility of iVas-MRI in predicting clinical outcomes in a cross-sectional setting. Then, through serial MRIs, we will examine the utility of iVas-MRI in differentiating treatment benefits of two most commonly performed surgical procedures in Moyamoya patients, specifically direct versus indirect bypass surgery. The long-term impact of this work on clinical practice is that patients with cerebrovascular diseases will have their vascular imaging scan done in just one visit of less than 10 minutes (as opposed to multiple visits and several scans). Additionally, patients who are allergic to conventional contrast agent will have access to an alternative contrast agent (i.e. O2 and CO2 gases) for their vascular imaging needs.